I have made an excel ribbon. In that ribbon, there are few buttons which I want to disable if the filename doesn't contain specific string. So I put the logic in ExcelRibbon_load() event. But the problem is ExcelRibbon_Load() is fired only at the time of opening new excel window. If user opens correct file afterwards in the same window, the buttons would remain disabled.So, I want to detect the opening of new file in same excel window (Like File->Open->FileName) programmatically via C#. Any idea how to achieve this. Any help is welcome.